12684391 has 4 divisors (see below), whose sum is σ = 12698352. Its totient is φ = 12670432.

The previous prime is 12684389. The next prime is 12684403. The reversal of 12684391 is 19348621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19348621 = 563 ⋅34367.

It is a cyclic number.

It is not a de Polignac number, because 12684391 - 2¹ = 12684389 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12684361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5515 + ... + 7468.

It is an arithmetic number, because the mean of its divisors is an integer number (3174588).

Almost surely, 2^12684391 is an apocalyptic number.

12684391 is the 2253-rd centered pentagonal number.

12684391 is a deficient number, since it is larger than the sum of its proper divisors (13961).

12684391 is an equidigital number, since it uses as much as digits as its factorization.

12684391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13960.

The product of its digits is 10368, while the sum is 34.

The square root of 12684391 is about 3561.5152674108. The cubic root of 12684391 is about 233.2150323213.

The spelling of 12684391 in words is "twelve million, six hundred eighty-four thousand, three hundred ninety-one".